Dewald Daryll B, Ozaki Shoichiro, Malaviya Swati, Shope Joseph C, Manabe Kelly, Crosby Lee, Neilsen Paul, Johnston Derrick, Harihar Sitaram, Prestwich Glenn D
Department of Biology, Utah State University, Logan, 84322-5305, USA.
Cell Calcium. 2005 Aug;38(2):59-72. doi: 10.1016/j.ceca.2005.06.004.
Intracellular calcium Ca(2+) is mobilized in many cell types in response to activation of phosphoinositide (PIP(n)) signaling pathways involving PtdIns(4,5)P(2) or PtdIns(3,4,5)P(3). To further explore the relationship between increases in intracellular PIP(n) concentrations and mobilization of Ca(2+), each of the seven phosphorylated phosphoinositides (PIP(n)s) were delivered into cells and the metabolism and physiological effects of the exogenously administered PIP(n)s were determined. The efficient cellular delivery of fluorophore-tagged and native PIP(n)s was accomplished using histone protein, neomycin, and dendrimeric polyamines. PtdIns(4,5)P(2) fluorophore-tagged analogs with short- and long-acyl chains were substrates for cellular enzymes in vitro and for phospholipases in stimulated fibroblasts. PtdIns(4)P, PtdIns(3,4)P(2) and PtdIns(4,5)P(2), each induced calcium mobilization rapidly after exogenous addition to fibroblasts. PtdIns(3,4,5)P(3) induced a significant, but smaller increase in intracellular calcium. These observations suggest that PIP(n)s other than PtdIns(4,5)P(2) or PtdIns(3,4,5)P(3) may have direct roles in signaling involving Ca(2+).
细胞内钙Ca(2+)在许多细胞类型中，会因涉及磷脂酰肌醇(PIP(n))信号通路（涉及磷脂酰肌醇-4,5-二磷酸(PtdIns(4,5)P(2))或磷脂酰肌醇-3,4,5-三磷酸(PtdIns(3,4,5)P(3))）的激活而被动员。为了进一步探究细胞内PIP(n)浓度升高与Ca(2+)动员之间的关系，将七种磷酸化磷脂酰肌醇(PIP(n)s)中的每一种都导入细胞，并确定外源性给予的PIP(n)s的代谢和生理效应。使用组蛋白、新霉素和树枝状多胺实现了荧光团标记的天然PIP(n)s的高效细胞递送。带有短酰基链和长酰基链的荧光团标记的PtdIns(4,5)P(2)类似物在体外是细胞酶的底物，在受刺激的成纤维细胞中是磷脂酶的底物。外源性添加到成纤维细胞后，磷脂酰肌醇-4-磷酸(PtdIns(4)P)、磷脂酰肌醇-3,4-二磷酸(PtdIns(3,4)P(2))和磷脂酰肌醇-4,5-二磷酸(PtdIns(4,5)P(2))每种都迅速诱导钙动员。磷脂酰肌醇-3,4,5-三磷酸(PtdIns(3,4,5)P(3))诱导细胞内钙有显著但较小的增加。这些观察结果表明，除PtdIns(4,5)P(2)或PtdIns(
